The aim of this study is to determine the effect of vasectomy on the shedding of HIV in the semen from HIV-infected men. We hypothesize that the decrease in mononuclear cells following vasectomy will result in a decrease in the recovery of HIV. The long-term objectives are to provide insight into the mechanisms of HIV shedding in semen; help evaluate vasectomy as an adjunct method for reducing shedding of HIV in semen; and provide information that can be directed at educational and social strategies to limit the sexual transmission of HIV, particularly since vasectomy is the safest, simplest and most effective method of contraception and is available worldwide. We have in storage at the University of Washington, Seattle, 135 semen specimens from 28 HIV seropositive men and 30 specimens from 10 seronegative men before and after vasectomy. These specimens were obtained from a collaborative project between the University of Washington and the Community Development Association, Bangkok, Thailand. We will complete an analysis of HIV DNA in the cell pellet of semen, obtained before and after vasectomy, using a polymerase chain reaction method developed by our foreign scientist collaborator, Dr. Nikolaeva. We will also apply a recently developed monoclonal antibody-coated microparticle HIV-capture method, followed by RNA reverse transcript ion and DNA PCR, to detect cell-free. HIV RNA in the seminal plasma from this specimen collection. These results will either confirm or refute the hypothesis that shedding of HIV in the semen ejaculate of HIV Seropositive men can be decreased by vasectomy.